Insulating roof deck structure



Oct. 5, 1965 J. w. DONEGAN 3,209,502

INSULATING ROOF DECK STRUCTURE Filed June 7, 1961 LMA:

INVENTOR JOSEPH W. DONEGAN BY M. fa;

ATTORNEY United States Patent O 3,209,502 INSULATING ROOF DECK STRUCTURE Joseph Willard Donegan, Bergenfield, NJ., assignor to Allied Chemical Corporation, a corporation of New York Filed June 7, 1961, Ser. No. 115,388 3 Claims. (Cl. 52-394) This invention relates to an insulating structure having a continuous vapor barrier and to a composite insulating construction unit therefor.

Insulating roof deck units are currently being produced having vapor barriers for preventing passage of water vapor across the `barrier and into the interior of the insulating material on the other side thereof. The units typically each comprise superposed fibrous insulating boards and a vapor barrier intermediate and bonding the boards. The units generally are assembled through tongue and groove joints to form the roof deck.

In joining contiguous insulating units in a roof structure at their transverse short edges, tongue and groove joints require that the units be shoved laterally across the underlying roof beams with resultant damaging or defacing of the interior exposed decorative surfaces of the units. To minimize such damaging effects waxpaper beam covers have been used. Use of such covers, however, has not been satisfactory.

It has been proposed to join the transverse edges of contiguous insulating units by means of butt or ship-lap joints. However, the vapor barrier provided within such units has been discontinuous or not connected. The greatest danger of discontinuity in the vapor barrier at the butt or ship-lap joint arises from the free-path condensation of moisture as ice in cold weather, filling the joint and releasing as a surface-staining liquid when the weather becomes moderate. Moreover, moisture-containing air tends to pass upwardly through the discontinuity between the non-connected vapor barrier into the interior of the upper insulating board. By reason of the typical indoor temperatures and relative humidities employed in homes throughout a considerable portion of the country during the winter, e.g. 70 F. and 30% respectively, and the relatively low or below freezing outdoor temperature, e.g. 20 F., a dew point temperature tends to exist (for the existing humidity conditions) Within the roof deck structure at a location or level thereof not a great distance above the vapor barrier. Consequently, condensation of moisture from the air will occur at the plane or location of the dew point temperature with resultant deposition of water in the insulating material. Such water deposition is highly undesirable inasmuch as loss of insulating value, deterioration of fibrous insulating boards, blistering of paint from decorative surfaces, etc., is not infrequently attendant therewith. Furthermore, the absorption of moisture-containing air from within the building due to the vapor barrier discontinuity may promote formation of roof blisters. Under solar heat, the moisture-saturated air within the insulation expands greatly, forming the gas volumes and pressures which produce blisters in the roof. Additionally, the moisture within the insulating material is subject to freezing in cold weather, and the ice so formed may cause fracturing in portions of the roof due to expansive forces exerted thereby.

3,209,502 Patented Oct. 5, 1965 ICC It is, therefore, an object of this invention to provide an insulating structure, such as a roof deck structure, having a continuous and sealed vayor barrier between transverse edges of adjoining vapor barrier containing insulating units thereof, which continuous and sealed barrier will prevent passage of vapor from one side of the barrier to the other side thereof.

Another object of the invention is to provide a composite insulating structure having a modified ship-lap joint between transverse edges of adjoining vapor barrier-containing insulating units, which structure may be assembled without lateral movement of the insulating units.

Additional objects and advantages will be apparent as the invention is hereinafter described in detail.

It has now been found that a continuous and sealed vapor barrier between transverse edges of adjoining composite vapor barrier-containing insulating units may be achieved by providing modified ship-lap joints wherein the edges containing the vapor barrier have opposed complementary inclined faces, and a sealant is applied along the inclined faces coextensive with the vapor barrier to provide continuity of said vapor barrier between the transverse edges of adjoining units.

More specifically, the modified ship-lap joint is formed by providing transverse edges having opposed complementary faces composed of three sections, the lower and upper sections of each face being substantially vertical and the intermediate section of each face containing the vapor barrier being inclined upwardly joining the lower and upper sections. Preferably, each of the upper and lower sections forms an angle of about to 165 with the intermediate section (i.e., the angle between the Vertical section and inclined section of each face of the joint is about 105 to 165).

Not only does this manner of joining transverse edges of insulating units provide an extremely effective vaportight seal, but, further, the installation of adjacent units may be made Without horizontal shift, precluding damage to the decorative surfaces of the units. Thus, superposition of the adjacent insulating unit automatically effects continuity between the exposed transverse edges of the vapor barriers of the units. Moreover, the inclined faces of the joints expose the vapor barrier so as to provide a guide for easy application of the sealant to the desired area.

In the drawings:

FIGURE 1 is a fragmentary plan view of the preferred embodiment of the insulating roof deck structure of this invention having a sealed and continuous vapor barrier between transverse edges of adjoining vapor barrier-containing units making up the roof deck.

FIGURE 2 is a fragmentary side elevational view of the roof deck structure taken along line 2-2 of FIG- URE 1.

Referring to the drawings, composite insulating units 1 are joined or engaged edge to edge at their transverse sections through the modified ship-lap joint described below to form a roof deck structure, each unit comprising upper insulating board 2, relatively thin lower insulating board 3 providing an interior exposed decorative surface 4 (typically a painted surface) and continuous vapor barrier 5 of water vapor impervious material extending between and coextensive with and bonding the boards. Conventional roofing 6 is superimposed on upper insulating board 2. The insulating roof deck is supported by spaced joists designated by 7.

The transverse edges 8 and 8 of adjoining units 1 have opposed complementary faces composed of three sections. The lower sections of the faces, represented by 9 and 9', are substantially vertical and extend upwardly from the bottom of insulating board 2 to somewhat below vapor barrier 5. The intermediate sections of the faces, represented by 11 and 11', are inclinded upwardly (either inwardly or outwardly) and extend from somewhat below to somewhat above vapor barrier 5. The upper sections of the faces, represented by 12 and 12', are substantially vertical and extend upwardl to the top of insulating board 3. The angle formed between each of the lower and upper sections and the intermediate section varies between 105 and 165.

The ends of vapor barrier extend to and terminate within complementary inclined faces 11 and 11' of units 1. A sealant 13 is disposed along the inclined faces coextensive with the vapor barrier to provide a continuous land sealed vapor barrier between the transverse edges of the units. Since the ends of the vapor barrier are exposed and easily visible on the inclined face, the sealant is readily applied in the eld in proper alignment.

Units 1 are joined at their longitudinal edges through tongue and groove points (not shown) with a sealant disposed in the groove of each joint contacting and connecting the vapor barrier edges to .also provide a continuous and sealed vapor barrier between the longitudinal edges of t-he units. Preferably, the tongue and groove joints are those described in my copending application Serial No. 719,151, filed March 4, 1958, now U.S.P. 3,079,730 of March 5, 1963.

As indicated above, joining of the transverse edges of the insulating units may be made without horizontal shift, thereby precluding damage to the decorative surfaces of the units. The longitudinal (tongue and groove) edges may be joined by simply tipping the units in place. However, even if the longitudinal edges are slid into place, any marring of the decorative surfaces will not be visible.

The upper and lower boards of each roof deck unit are typically conventional wood libre insulating boards. The upper boards may be impregnated with asphalt, while the lower boards which provide the exposed decorative surface are generally not impregnated. If desired, the boards can be fabricated or made of other fibrous insulating material, such as wood pulp, bagasse, ax, straw or ground wood.

The continuous vapor barrier can be made of adhesive or non-adhesive water vapor impervious or substantially impervious material, e.g. asphalt, pitch, polyethylene, aluminum, cellulose acetate, plasticized polyvinyl chloride composition, polyester lm or rubberlike materials. While not necessary to successful practice of the invention, it is often desirable to support or bond such barrier, .particularly when formed of non-adhesive material, between paper sheets, which paper-covered barrier can be relatively easily bonded to the insulating boards using conventional aqeuous adhesive. However, it is to be understood that a non-adhesive barrier not covered with paper could be directly bonded to the boards, if desired, with any suitable adhesive material. Excellent results have been obtained when the barrier is a composition containing, by Weight, polyvinyl chloride i0-60%, pitch 30-40% and dioctyl phthalate 15-20% (the pitch and phthalate being plasticizers), and this barrier (typically 4 mils thick) is bonded or calendered between two paper sheets.

Continuity of vapor barrier ends of adjoining insulating units is effected by use of a held-applied adhesive or caulking material as sealant. The material may 'be a conventional mastic composition comprising mineral fillers in a vehicle of drying or non-drying oils, gums or resins.

'Such composition may include a solvent cutback, aqueous emulsion, non-setting Vehicle or internally-setting resin. An isocyanate foam composition is also well suited for use as sealant. The important criteria in selection of a suitable sealant are (l) heavy consistency which will form a nonflowing, but pressure deformable, bead on the inclined faces at the vapor barrier level, (2) permanent retention of continuity between opposed vapor barrier termini, (3) impermeability to water vapor .and (4) elasticity to permit movement of the structure without rupture of sealant.

Although certain preferred embodiment of the invention have been discussed for purposes of illustration, it wil-l be evident that various changes and modifications may be made therein without departing from the scope and spirit of the invention.

I claim:

1. In an insulating roof deck structure comprising composite insulating units joined edge to edge, each unit comprising a pair of superposed boards of fibrous insulating material, a vapor barrier extending between the boards and terminating at the edges of the units and a sealant contacting the ends of the vapor barrier, the improvenient which comprises providing at the transverse short edges of the units modified ship-lap joints wherein the edges containing the vapor barrier have opposed complementary inclined faces, and the sealant is applied along the inclined faces coextensive with the vapor barrier to provide continuity of said vapor barrier between the transverse edges of adjoining units.

2. In an insulating roof deck structure comprising composite insulating units joined edge to edge, each unit comprising a pair of superposed boards of librous insulating material, a vapor barrier extending between the boards and terminating at the edges of the units and a sealant contacting the ends of the vapor barrier, the improvement which comprises providing tat the transverse short edges of the units modified ship-lap joints wherein the edges have opposed complementary faces composed of three sections, the lower and upper sections of each face being substantially vertical and the intermediate section of each face containing the vapor barrier being inclined upwardly joining the lower and upper sections, and the sealant is applied along the inclined faces coextensive with the Vapor barrier to provide continuity of said vapor barrier between the transverse edges of adjoining units.

3. In an insulating roof deck structure comprising composite insulating units joined edge to edge, each unit com prising a pair of superposed boards of fibrous insulating material, a vapor barrier extending between the boards and terminating at the edges of the units and a sealant contacting the ends of the vapor barrier, the improvement which comprises providing at the transverse short edges of the units modified ship-lap joints wherein the edges have opposed complementary faces composed of three sections, the lower and upper sections of each face being substantially vertical and the intermediate section of each face containing the vapor barrier being inclined upwardly joining the lower and upper sections to form an angle with each of said lower and upper sections of about to and the sealant is applied along the inclined faces coextensive with the vapor barrier to provide continuity of said vapor barrier between the transverse edges of adjoining units.

References Cited by the Examiner UNITED STATES PATENTS 408,066 7/89 Beaumont 50--410 502,289 8/-93 Feldmann 20-8 1,083,243 12/13 Edwards 50-238 1,374,082 4/ 21 Hedges 20-8 1,863,231 6/32 Thune 20-92 X 2,152,694 4/39 Hoover 20-92 X 2,192,458 3/40 Swenson et al 50-456 (Other referenceson following page) 5 UNITED STATES PATENTS 892,052 10/53 12/45 Fink 20-5 248,515 3/26 4/58 seme 50-346 5411733 12/41 2/59 paul 50-346 491077 2/31 5/59 Knold 50-225 5 1241957 4/28 FOREIGN PATENTS 4/51 Austria. 11/54 Canada.

Germany. Great Britain. Great Britain. Norway. Switzerland.

WILLIAM I. MUSHAKE, JACOB L. NACKENOFF,

Examiners.

HENRY C. SUTHERLAND, Primary Examiner. 

1. IN AN INSULATING ROOF DESK STRUCTURE COMPRISING COMPOSITE INSULATING UNITS JOINED EDGE TO EDGE, EACH UNIT COMPRISING A PAIR OF SUPERPOSED BOARDS OF FIBROUS INSULATING MATERIAL, A VAPOR BARRIER EXTENDING BETWEEN THE BOARDS AND TERMINATING AT THE EDGES OF THE UNITS AND A SEALANT CONTACTING THE ENDS OF THE VAPOR BARRIER, THE IMPROVEMENT WHICH COMPRISES PROVIDING AT THE TRANSVERSE SHORT EDGES OF THE UNITS MODIFIED SHIP-LAP JOINTS WHEREIN THE EDGES CONTAINING THE VAPOR BARRIER HAVE OPPOSED COMPLEMENTARY INCLINED FACES, AND THE SEALANT IS APPLIED ALONG THE INCLINED FACES COEXTENSIVE WITH THE VAPOR BARRIER TO PROVIDE CONTINUITY OF SAID VAPOR BARRIER BETWEEN THE TRANSVERSE EDGES OF ADJOINING UNITS. 